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Aug 11, 2016CSB Safety Alert: Preventing High Temperature Hydrogen Attack (HTHA) - Related Safety Bulletin
The CSB’s investigation into the catastrophic failure of a forty-year-old heat exchanger at the Tesoro Refinery determined that the fatal explosion and fire was caused by a damage mechanism known as high temperature hydrogen attack, or HTHA, which severely cracked and weakened the carbon steel heat exchanger over time, leading to a rupture. The CSB’s report released in May 2014 concluded that the standard industry uses for determining vulnerability of equipment to HTHA is inadequate. To address its findings, the CSB made recommendations intended to prevent HTHA to the industry group that issues guidance on HTHA, the American Petroleum Institute (API). Because of these noted deficiencies, the Board voted on July 13, 2016, to designate the Recommendation 2010-08-I-WA-R10 with the status of Closed – Unacceptable Action. In the absence of industry guidance that incorporates findings from the Tesoro Anacortes failure, the CSB is issuing a safety alert to provide additional direction for industry.